Prevention of Postoperative Delirium in Surgical Patients

Risk Factors and Patient Assessment

The American Society of Anesthesiologists (ASA) identifies advanced age, male sex, higher BMI, lower education level, smoking history, previous delirium episodes, institutionalization, comorbidities, and polypharmacy as independently associated with postoperative delirium (POD) 3, 4
Elevated serum inflammation markers increase delirium risk in surgical patients 3
Higher ASA status and longer duration of surgery/anesthesia are significant predictors of postoperative delirium 3, 4
Preoperative risk assessment should identify high-risk patients using factors such as age, comorbidities, and previous delirium history 3, 9

Deeper anesthesia (BIS values around 35) is associated with higher delirium rates compared to lighter anesthesia (BIS values around 50) 2, 5
Excessive anesthetic depth causing burst suppression patterns increases delirium risk 2, 5
Intraoperative ketamine does not reduce delirium risk and may increase hallucinations and nightmares 6
Intravenous opioids are associated with higher delirium rates compared to oral opioids 7
The American College of Anesthesiologists recommends maintaining BIS values around 50 to reduce delirium incidence 2
Monitor anesthesia depth using processed EEG monitoring (such as BIS) in patients over 60 years to avoid excessive anesthetic depth and prevent hypotension 2, 5

Regional nerve blocks can reduce delirium incidence, severity, and duration in orthopedic surgery patients 1, 8
Fascia iliaca blocks for hip fracture surgery can reduce delirium incidence (10.78% vs 23.8%) 1, 8
Femoral nerve catheters for knee arthroplasty can lower delirium rates (25% vs 61%) 1

Multimodal analgesia can minimize delirium risk by reducing opioid use 7
Non-opioid analgesics, such as scheduled acetaminophen and NSAIDs, can be used when not contraindicated 7
Limit use of tramadol and meperidine, which have been linked to increased delirium risk 7
Oral administration of opioids is associated with lower delirium risk than intravenous routes 7

Anesthetic agent selection should prioritize depth of anesthesia over specific agent choice 2, 5
Postoperative nausea and vomiting (PONV) prevention using multimodal prophylaxis can reduce PONV, which can contribute to delirium 2
Temperature management to prevent hypothermia can reduce delirium risk 2